AP Bio: Meiosis Quiz

What is the function of meiosis?

to create sperm and egg cells called gametes (sex cells)

What type of organs are the cells that enter meiosis found?

ovaries (female) testis (male)

Prophase I

DNA condenses, paring of homologous chromosomes to form a tetrad, and crossing over occurs

Metaphase I

tetrads line up along the metaphase plate, and are independently assorted

Anaphase I

tetrads (homologous chromosomes) move to opposite sides of the cells

Telophase I

each nuclei now has half the number of chromosomes

Cytokinesis I

2 haploid cells are formed

Prophase II

DNA condenses

Metaphase II

chromosomes line up on the metaphase plate (middle of the cell)

Anaphase II

sister chromatids are separated

Telophase II

4 nuclei now have half the number of chromosomes

Cytokinesis II

you now have 4 haploid cells

Haploid

23 chromosomes or half the number of chromosomes

Diploid

46 chromosomes or the same number of chromosomes

If a cell starts as diploid, what does it end up as after meiosis?

will end up with 4 haploid cells

If a cell starts as diploid, what does it end up as after mitosis?

will end up with 1 other diploid cell

Are the number of chromosomes reduced in meiosis? If so what is it reduced to for human cells?

From 46 to 23.

What happens to the chromosome number after fertilization?

again become diploid and have 46 chromosomes

What becomes divided in meiosis I?

tetrads (homologous chromosomes)

What becomes divided in meiosis II?

sister chromatids

What is crossing over and when does this occur?

is the exchange of different segments of genetic material and occurs in prophase 1

What is the chiasma?

a point of overlap of paired chromatids at which fusion and exchange of genetic material take place during prophase of meiosis I

What are recombinant chromatids?

the chromatids that have exchanged genetic material

How does crossing over contribute to genetic diversity of the gametes?

it allows for DNA to be exchanged so chromosomes do not have the exact same genetic material as their parents

What is independent assortment and when does this occur in meiosis?

it is the formation of random combinations of chromosomes metaphase 1

What are three ways in which sexual reproduction introduces genetic variation/diversity? Why is genetic diversity important from an evolutionary standpoint?

Genetic recombination/Crossing over /Random Fertilization; Provides variation for natural selection to occur.